A font is a family of characters of a given style, typically used in printing. A font character is one symbol in the font.
In computer printing systems, fonts are often stored in a printer's memory and accessed by commands from a host computer. The more characters in the font, the more memory that is needed.
Often users desire to print with more than one font. For example, a user may wish to italicize a word, or to use smaller letters. The italicized and small characters would constitute different fonts. Courier 12-point is a particular font. The word "point" refers to a unit of type measurement equal to 1/72-of-an-inch, so "12-point" refers to characters that are 1/6-of-an-inch tall. Courier 12-point italic and Courier 10-point are both different fonts, one having italicized characters and the other having smaller characters.
Additional memory is needed to store additional fonts in a printer, such as italicized fonts and small character fonts. But memory is expensive, so printers with multiple fonts are also expensive.
The invention compresses more fonts into a fixed-size memory. Thus, multiple fonts may be used with a smaller memory.